Wireless Radio System for Adjusting Path Loss Calculations

ABSTRACT

There is provided a wireless radio system comprising compensation circuitry to adjust, based on a scan loss of an outgoing signal due to beamforming, a transmission power of the outgoing signal by a scan loss adjustment amount to produce an adjusted signal. Transmission circuitry transmits the adjusted signal and reception circuitry receives an incoming signal at a reception power. Calculation circuitry performs a calculation of a path loss based on a difference between the transmission power and the reception power and adjusts the path loss. Reporting circuitry reports an indication of the path loss adjusted by the calculation circuitry to the base station. The calculation circuitry adjusts the path loss based on the scan loss adjustment amount.

The present disclosure relates to a wireless radio system and inparticular to adjustment of transmission power of the wireless radiosystem.

Beamforming is used in wireless communication to transmit wirelesssignals. Such transmission methods suffer from scan losses which arecharacterised by a reduction in transmission power dependent on thebeamforming. In order to improve transmission power the outgoing signalcan be adjusted by a scan loss adjustment amount to compensate for thereduction in transmitted power. However, this leads to a discrepancybetween the power of the transmitted signal and reception power of anincoming signal and can result in an overall reduction in transmissionefficiency.

Viewed from a first example configuration, there is provided a wirelessradio system comprising: compensation circuitry to adjust, based on ascan loss of an outgoing signal due to beamforming, a transmission powerof the outgoing signal by a scan loss adjustment amount to produce anadjusted signal; transmission circuitry to transmit the adjusted signal;reception circuitry to receive an incoming signal at a reception power;calculation circuitry to perform a calculation of a path loss based on adifference between the transmission power and the reception power, andto adjust the path loss; and reporting circuitry to report an indicationof the path loss adjusted by the calculation circuitry to the basestation, wherein the calculation circuitry adjusts the path loss basedon the scan loss adjustment amount.

Viewed from a second example configuration, there is provided a methodcomprising: adjusting, based on a scan loss of an outgoing signal due tobeamforming, a transmission power of the outgoing signal by a scan lossadjustment amount to produce an adjusted signal; transmitting theadjusted signal; receiving an incoming signal at a reception power;performing a calculation of a path loss based on a difference betweenthe transmission power and the reception power, and to adjust the pathloss; and reporting an indication of the path loss adjusted by thecalculation circuitry to the base station, wherein the path loss isadjusted based on the scan loss adjustment amount.

Viewed from a third example configuration, there is provided a wirelessradio system comprising: means for adjusting, based on a scan loss of anoutgoing signal due to beamforming, a transmission power of the outgoingsignal by a scan loss adjustment amount to produce an adjusted signal;means for transmitting the adjusted signal; means for receiving anincoming signal at a reception power; means for performing a calculationof a path loss based on a difference between the transmission power andthe reception power, and to adjust the path loss; and means forreporting an indication of the path loss adjusted by the calculationcircuitry to the base station, wherein the path loss is adjusted basedon the scan loss adjustment amount.

The present technique will be described further, by way of example only,with reference to embodiments thereof as illustrated in the accompanyingdrawings, in which:

FIG. 1 schematically illustrates a wireless radio system which mayembody various examples of the present techniques;

FIG. 2a schematically illustrates array gain of a steered beam which mayembody various examples of the present techniques;

FIG. 2b schematically illustrates array gain of a steered beam which mayembody various examples of the present techniques;

FIG. 3a schematically illustrates maximum array gain of steered beamswhich may embody various examples of the present techniques;

FIG. 3b schematically illustrates additional power applied to signals tocompensate for scan loss which may embody various examples of thepresent techniques;

FIG. 4a schematically illustrates resource block allocation which mayembody various examples of the present techniques;

FIG. 4b schematically illustrates resource block allocation which mayembody various examples of the present techniques;

FIG. 5 schematically illustrates a wireless radio system which mayembody various examples of the present techniques;

FIG. 6a schematically illustrates a sequence of steps carried out by abase station which may embody various examples of the presenttechniques;

FIG. 6b schematically illustrates a sequence of steps carried out by awireless radio system which may embody various examples of the presenttechniques;

FIG. 6c schematically illustrates a sequence of steps carried out by awireless radio system which may embody various examples of the presenttechniques;

FIG. 7 schematically illustrates a sequence of steps carried out by awireless radio system which may embody various examples of the presenttechniques; and

FIG. 8 schematically illustrates a sequence of steps carried out by awireless radio system which may embody various examples of the presenttechniques.

Before discussing the embodiments with reference to the accompanyingfigures, the following description of embodiments and associatedadvantages is provided.

In accordance with one example configuration there is provided awireless radio system comprising: compensation circuitry to adjust,based on a scan loss of an outgoing signal due to beamforming, atransmission power of the outgoing signal by a scan loss adjustmentamount to produce an adjusted signal; transmission circuitry to transmitthe adjusted signal; reception circuitry to receive an incoming signalat a reception power; calculation circuitry to perform a calculation ofa path loss based on a difference between the transmission power and thereception power, and to adjust the path loss; and reporting circuitry toreport an indication of the path loss adjusted by the calculationcircuitry to the base station, wherein the calculation circuitry adjuststhe path loss based on the scan loss adjustment amount.

The compensation circuitry is provided in order to compensate for thescan loss that occurs due to beamforming. In particular, scan loss(described in more detail below) occurs due to limitations in thetransmission power of the transmission circuitry and particularly itsinability to transmit at a maximum power over all angles. Thecompensation circuitry adjusts (e.g. boosts/amplifies, or attenuates)the signal so that the outgoing signal is stronger, in order tocompensate for this scan loss. However, when an incoming signal isreceived, it typically does not have the same adjustment made, and sothere is a mismatch between the transmitted power and the received powerwhen calculating the path loss. In these examples, the path losscalculation is adjusted and an adjusted path loss is reported to thebase station. The path loss is adjusted based on the scan lossadjustment amount. In this way, a more representative view of the pathloss can be considered by the base station for managing the network.

In some examples, the scan loss adjustment amount is limited to amaximum value so that the adjusted signal's transmission power is belowa regulatory limit. Regulatory limits could be set by governments inorder to prevent either unsafe transmission powers from being used or torestrict interference between users of the radio spectrum. In otherexamples the regulatory limit could relate to a limit as set in astandard.

In some examples, the transmission circuitry comprises an antenna arrayto steer a transmission beam corresponding to the outgoing signal at aplurality of angles, wherein the scan loss is dependent on a steereddirection, which is one of the plurality of angles at which thetransmission beam is steered. Multidirectional antenna arrays can beused to transmit a transmission beam at a variety of angles. These workby using a plurality of transmission elements that are set out along aplane and by varying the phase or the amplitude (or both phase andamplitude) of the signal provided to each of the plurality of antennaelements in order to generate a wave front at a particular steeredangle. In these examples, the scan loss is dependent on the steereddirection.

In some examples, a gain at the steered angle of the transmission beamtransmitted at the steered angle is below a gain at a peak transmissionangle of the transmission beam transmitted at the steered angle. When abeam is transmitted at a given angle, it might have a different power atthe given angle than at other angles. For instance, if a beam istransmitted at 90 degrees, then the power of that beam at 90 might be 5dB whereas the power of the same beam at 60 degrees could be 0 dB. Thatis, the power of the beam changes as one moves away from the steereddirection.

In some examples, the scan loss is a difference between a maximum gainof the antenna array across all of the plurality of angles and a maximumgain of the transmission beam transmitted at the steered angle. In otherwords, the transmission beam is the beam generated at the desiredsteered angle. The scan loss is a function of the steered angle and, ata given steered angle the scan loss is the difference between a peakpower measured for the antenna array across all steered angles and thepeak power output measured for the given steered angle

In some examples, the transmission circuitry is adapted to transmit theadjusted signal to a wireless node during a subset of a plurality ofresource blocks; and the reception circuitry is adapted to receive theincoming signal from the wireless node. The wireless node could, forinstance, take the form of a base station. The resource blocks determinean interval (e.g. in time and/or frequency) that can be used by thewireless radio system to transmit the adjusted signal to the wirelessnode and an interval in time that can be used for the wireless node tocommunicate with the wireless radio system.

In some examples, the wireless node is configured to allocate the subsetof the plurality of resource blocks to the wireless radio system. Thebase station can therefore participate (possibly with informationprovided by other nodes) a management role within the network forallocating the resource blocks.

In some examples, the wireless node is configured to allocate the subsetof the plurality of resource blocks to the wireless radio system basedon the path loss reported by the reporting circuitry of the wirelessradio system. The wireless node and the wireless radio system togetherdetermine the allocation of resource blocks based on the signal pathloss. In particular, the wireless radio system can determine path lossfrom the wireless node based on knowledge of the transmitted power ofthe adjusted (transmitted) signal and the received power of the adjustedinput (received) signal.

In some examples, the path loss is adjusted by compensating for the scanloss adjustment amount. By adjusting the path loss that is reported tothe base station, the scan loss adjustment amount can be compensatedfor, therefore performing scan loss adjustment without the scan lossadjustment itself influencing the path loss calculation (and thereforethe assignment of the resource blocks).

In some examples, the path loss is adjusted by discounting the scan lossadjustment amount. For example, the path loss could be adjusted bysubtracting the scan loss adjustment amount from the rest of the pathloss calculation. In this way, the scan loss adjustment amount has nobearing on the path loss calculation.

In some examples, the compensation circuitry is an amplifier. Theamplifier can therefore perform amplification on the outgoing signal bythe scan loss adjustment amount. In other embodiments, the compensationcircuitry might attenuate the outgoing signal based on the scan lossadjustment amount to produce the adjusted signal.

In some examples, the outgoing signal and the adjusted signal are RFsignals. Radio frequency (RF) signals can be used to transmit data overa large range.

In some examples, the wireless radio system comprises furthercompensation circuitry to adjust a power of a baseband signal to producethe outgoing signal at the transmission power.

The present technique can also be configured in the following ways:

At least some related examples provide a wireless radio systemcomprising: compensation circuitry to adjust, based on a scan loss of anoutgoing signal due to beamforming, a transmission power of the outgoingsignal by a scan loss adjustment amount to produce an adjusted signal;transmission circuitry to transmit the adjusted signal; receptioncircuitry to receive an incoming signal at a reception power; and inputadjustment circuitry configured to adjust the reception power of theincoming signal based on the scan loss adjustment amount to produce anadjusted input signal.

In order to compensate for the scan loss, there is provided compensationcircuitry to adjust/amplify the outgoing signal by the scan lossadjustment amount and to increase the power of the outgoing signal.However, the inventors have realised that such adjustment leads to adiscrepancy between the transmitted power and the received power. Thisdiscrepancy can result in a reduction in throughput of the wirelessradio system. Hence, the wireless radio system is provided with inputadjustment circuitry to adjust the reception power of the incomingsignal based on the scan loss adjustment amount. The adjustment can takevarious forms, for example, the incoming signal can be adjusted by thescan loss adjustment amount such that a same adjustment is applied toboth the outgoing signal and the incoming signal. In this way theoutgoing signal is adjusted/amplified to compensate for the scan lossand the discrepancy introduced by the compensation circuitry isovercome. Alternatively, the adjustment circuitry could be configured toadjust/amplify the incoming signal to further compensate for additionaladjustment/amplification applied to the incoming signal when it wastransmitted.

The precise form of the scan loss adjustment amount can vary dependingon implementation. However, in at least some related examples the scanloss adjustment amount is limited to a maximum value so that theadjusted signal's transmission power is below a regulatory limit. Due tothe regulatory limits, the power of the outgoing signal cannot beboosted arbitrarily. In addition, as the scan loss is dependent on thebeamforming the effects of the scan loss may be greater in some casesthan in others. As a result the scan loss adjustment amount depends onthe beamforming and the compensation circuitry adjusts the outgoingsignal to provide power output limited by the regulatory limitindependent of the beamforming.

In at least some related examples the transmission circuitry comprises aplurality of antenna elements to steer a transmission beam at aplurality of angles, and wherein the scan loss is dependent on atransmission angle of the plurality of angles. The antenna elements forma wireless antenna array to transmit, as the transmission beam, theadjusted signal. Due to scan losses the plurality of antenna elementsoutput the transmission beam with power that is dependent on thetransmission angle. For example, a beam transmitted in a directionnormal to the surface of the antenna elements may have a peak power thatis higher than a beam transmitted at an angle that is different from thedirection normal to the surface of the antenna elements. In such relatedexamples, in order to compensate for the scan loss, the scan lossadjustment amount is dependent on the transmission angle of theplurality of angles.

In some related examples the transmission angle is determined based onat least a relative phase shift between signals transmitted fromadjacent elements of the plurality of antenna elements. By varying thephase of the signal provided to adjacent elements of the plurality ofantenna elements, the antenna elements can be configured to transmitradio waves that add up constructively in the beam steering directionresulting in a transmission beam that is transmitted in the direction ofthe beam steering angle.

The variation in power output by the antenna array for different angles(array gain) contributes to determine the power output by the antennaarray. Ideally, the gain in the direction determined by the steeredangle would be the peak gain output by the antenna array for that beamsteering angle. However, in at least some related examples a gain at thesteered angle of the transmission beam transmitted at the steered angleis below a gain at a peak transmission angle of the transmission beamtransmitted at the steered angle. This is because, when generating radiowaves that add up constructively in the beam steering direction,constructive interference also occurs in a direction different to thesteered angle. For a beam transmitted at the steered angle, a peak gainmay be observed at a peak transmission angle that is different to thesteered angle. The difference between the peak gain and the gain at thesteered angle is referred to as the drop off. For beam steering anglesfor which the drop off is non-zero, it is not possible to amplify thesignal at the steered angle to the regulatory limit without exceedingthe regulatory limit at the peak transmission angle. In such relatedexamples, the scan loss adjustment amount is chosen to compensate forthe scan loss whilst taking the drop off into account. For example, thescan loss adjustment amount is limited by the drop off. In this waysignal power can be amplified without exceeding the regulatory limit.

In at least some related examples the scan loss is a difference betweena maximum gain of the antenna array across all of the plurality ofangles and a maximum gain of the transmission beam transmitted at thesteered angle. In other words, the transmission beam is the beamgenerated at the desired steered angle. The scan loss is a function ofthe steered angle and, at a given steered angle the scan loss is thedifference between a peak power measured for the antenna array acrossall steered angles and the peak power output measured for the givensteered angle.

In at least some related examples the transmission circuitry is adaptedto transmit the adjusted signal to a wireless node during a subset of aplurality of resource blocks; and the reception circuitry is adapted toreceive the incoming signal from the wireless node. The wireless nodecan take different forms. However in some related examples, the wirelessnode is a base station with which the wireless radio system is incommunication. The resource blocks determine an interval (e.g. in timeand frequency) that can be used by the wireless radio system to transmitthe adjusted signal to the wireless node and an interval in time andfrequency that can be used for the wireless node to communicate with thewireless radio system.

In at least some related examples the wireless node is configured toallocate the subset of the plurality of resource blocks to the wirelessradio system. The wireless node allocates the resource blocks to be usedby the wireless radio system defining when the wireless radio system cantransmit the adjusted signal and receive the incoming signal.

In at least some related examples the wireless radio system furthercomprises: calculation circuitry to perform a calculation of signal pathloss; and reporting circuitry to report an indication of the path lossto the wireless node, wherein the wireless node is configured toallocate the subset of the plurality of resource blocks to the wirelessradio system based on the path loss reported by the reporting circuitryof the wireless radio system. The wireless node and the wireless radiosystem together determine the allocation of resource blocks based on thesignal path loss. In particular, the wireless radio system can determinepath loss from the wireless node based on knowledge of the transmittedpower of the signal transmitted by the wireless node and the receivedpower of the adjusted input (received) signal. The wireless radio systemis therefore able to report an accurate value for the signal path lossto the wireless node. As a result the allocation of resource blocks isaccurately carried out resulting in an increased transmissionefficiency. In some related examples the power of the signal transmittedby the base station is encoded into the signal transmitted by thewireless node. In alternative related examples, the power of the signaltransmitted by the base station is known a-priori by the wireless radiosystem.

In at least some related examples the wireless node is at an angle thatdiffers from an angle at which any of the antenna elements has its peakgain. The wireless node is at an angle defined as the angular differencebetween a direction normal to the surface of the antenna elements and adirection of the wireless node from the surface of the antenna elements.The angle at which any of the antenna elements has its peak gain isdefined as the angular difference between the direction normal to thesurface of the antenna elements and a direction from the surface of theantenna elements in which the peak gain is measured. The angle of thewireless node differs from the angle at which any of the antennalelements has its peak gain when the direction of the wireless node fromthe antenna elements is not the same as the direction in which the peakgain is measured. As discussed this difference is due to the drop offassociated with the antenna elements and is taken into account in thescan loss adjustment amount.

In at least some related examples the compensation circuitry is anamplifier. The gain applied by the amplifier is dependent on a steeredangle of the transmission beam and is set to the scan loss adjustmentamount to amplify the outgoing signal at the steered angle to producethe adjusted signal.

In some related examples the input adjustment circuitry is an amplifier.The gain of the input adjustment circuitry is also set to the scan lossadjustment amount to amplify the incoming signal at the steered angle toproduce the adjusted input signal.

In some related examples the amplifier is a low noise amplifier. The lownoise amplifier amplifies the incoming signal without significantlydegrading its signal to noise ratio. In this way an accurate measurementof path loss can be determined from the adjusted incoming signal.

In at least some related examples the outgoing signal and the adjustedsignal are RF signals. RF (Radio Frequency) signals provide the means totransmit information over large distances enabling communication betweenthe wireless radio system and a base station.

In at least some related examples the wireless radio system comprisesfurther compensation circuitry to adjust a power of a baseband signal toproduce the outgoing signal at the transmission power. The furthercompensation circuitry, which adjusts/amplifies the baseband signal cantake different forms. However, in some related examples, the furthercompensation circuitry is an amplifier. The role of the furthercompensation circuitry is to amplify the outgoing signal, subject toparticular power constraints, which constrain the power output of thebaseband unit, to improve communication with the compensation circuitryand the antenna array.

Particular embodiments will now be described with reference to thefigures.

In air to ground wireless communication, user equipment on an aircraftmust communicate with a base station situated in a fixed location. Thisis achieved through the use of a steerable antenna mounted on theaircraft. The antenna is typically composed of an array of antennaelements and beam steering circuitry to direct a wireless communicationbeam towards the base station.

FIG. 1 illustrates a wireless radio system according to someembodiments. The wireless radio system comprises user equipment 10 andbase station 20. The user equipment 10 comprises a baseband and RF unit14, control circuitry 15, antenna system 12, and antenna array 22. Theantenna system 12 can be located in a position that is physicallydistinct from the baseband and RF unit 14 within an aircraft. Forexample, the antenna system could be located under the fuselage on anaircraft and the baseband and RF unit 14 could be located within theaircraft cockpit. The control circuitry 15 could comprise calculationcircuitry and/or reporting circuitry which will be further discussedbelow. The baseband and RF unit 14 comprises antenna control circuitry26, a first power amplifier 28 (PA1), a down convert unit 30 and abaseband unit 32. The baseband unit 14 is configured to operate subjectto particular power constraints which constrain the power output of thebaseband unit 14 to lower than the power output by the antenna system12. The role of the first power amplifier 28 is to adjust/amplify thepower output by the baseband unit 32 to improve communication with theantenna array. The power output by the baseband unit is constrained bythe power constraints of the baseband and, hence, it is not suitable forlong range communication with the base station 20. The role of theantenna system 12 is to adjust/amplify the power of the signal receivedfrom the baseband unit 32 for communication with the base station 20.Within antenna system 12 there is provided a second power amplifier 16(PA2) to compensate for scan loss, which is described in detail below.Antenna control unit 26 instructs the beam steering circuitry 18 toadjust the relative phase of signals transmitted to adjacent antennaelements of the antenna array 22 to generate a directional beam. Forexample, if each of the elements of the antenna array transmits in phasewith the adjacent antenna elements of the antenna array 22, then a beamis generated in a direction normal to the surface of the antenna array.As discussed, the transmitted power of the beam 24 formed by the antennaarray 22 is dependent on the beam steering angle and is referred to asthe array gain.

FIGS. 2a and 2b illustrate the variation in array gain as a function ofthe beam steering angle and the angle at which the array gain ismeasured. In addition to transmitting power in the direction intended bythe beam steering angle, a signal from the antenna array can be measuredat a range of angles. FIG. 2a illustrates the array gain measured for arange of angles for a beam directed with a beam steering angle such thatthe beam is transmitted in the direction normal to the surface of theantenna array. In the illustrated embodiment, beam steering circuitry 18(not shown) causes antenna array 22 to generate a beam with a beamsteering angle of zero degrees such that the beam is transmitted in thedirection normal to the surface of the antenna array. As discussed,power is not solely transmitted in this direction. Rather, if array gainwere to be measured using power meter 34 oriented at an angle ϑ to thenormal to the surface of the antenna array, an array gain as illustratedin FIG. 2a may be observed. In this example, the peak array gain 40occurs at the beam steering angle with array gain dropping off rapidlyas the power meter is moved away from this angle. In contrast, FIG. 2bschematically illustrates the array gain produced when the beam steeringcircuitry 18 causes antenna array 22 to generate a beam with an steeringangle ϕ to the normal to the surface of the antenna array. In this case,the array gain is seen to have a peak gain 36 at angle ϑ_(p) that islower than the peak gain 40 observed when the beam steering angle waszero degrees. The difference between the zero degree peak 40, i.e., themaximum gain over all beam steering angles and the maximum gain 36 forthe beam steered at angle 39 (ϑ=ϕ) is referred to as scan loss. Inaddition, the peak gain 36 is observed at an angle that is not equal tothat of the beam steering angle ϕ. The difference between the peak arraygain observed 36 at an angle ϑ=ϑ_(p) and the array gain at the beamsteering angle 38 (ϑ=ϕ) is referred to as the drop off.

FIG. 3a illustrates an example of array gain for four beams steered atbeam steering angles: ϕ=0 (line 70), ϕ=30 (line 72), ϕ=60 (line 74) andϕ=90 (line 76) degrees. The beams are generated using a uniform lineararray of antenna elements. Note the maximum gain is at the normal to thesurface of the antenna array, i.e. at 0 degrees yielding, e.g., an arraygain of 16 dBi. The solid line (line 78) illustrates the maximum arraygain as the beam steering angle ϕ is swept from −90 to 90 degrees. Theminimum array again is observed at the end-fire of the array, i.e. ϕ=−90or ϕ=90 degrees yielding, e.g., 6.3 dBi. In the absence of regulatorylimits, it would be theoretically possible to amplify the signal usingthe second power amplifier 16 to compensate for the difference betweenthe maximum gain over all beam steering angles and the gain for the beamsteered at angle 39 (ϑ=ϕ) measured at the beam steering angle 39 (ϑ=ϕ).However, due to the drop off, if the second power amplifier was set tocompensate for this difference, then a peak power greater than the zerodegree peak would be observed. For the example illustrated in FIG. 2b ,if the second power amplifier 16 was used to amplify the beam withsteering angle ϕ such that the total gain (the sum of the array gain andthe gain provided by the second power amplifier) at the steering anglewas equal to the regulatory limit, then a peak gain resulting in a poweroutput greater than the regulatory limit would be observed for beamsteering angle ϕ at the angle ϑ_(p). As a result the gain of the secondpower amplifier 16 for a beam steered at beam steering angle ϕ isproportional to the scan loss. The resulting radiated power for beamsteering angle ϕ measured at angle ϑ=ϕ is illustrated schematically byin FIG. 3a (line 80) corresponding to the radiated power labelled on theright hand axis. The decrease in radiated power observed as the angle isswept from ϕ=−90 to ϕ=90 is a result of the drop off and is required tomaintain a radiated power for beam steering angle ϕ below the regulatorylimit when measured at an angle different to the beam steering angle(ϑ≠ϕ). The corresponding additional power that is required by the secondpower amplifier 16 is illustrated in FIG. 3 b.

The inclusion of the second power amplifier 16 allows the power of thetransmitted signal to be increased to the regulatory maximum minus thedrop off over the whole range of beam steering angles ϕ. It is usuallyexpected that an increase in transmitted power would result in astronger and therefore faster wireless connection between the userequipment 10 and the base station 20. The inventors have realised thatthis is not the case. Rather, the amplification of the transmittedsignal using the second power amplifier 16 causes a discrepancy betweenthe Reference Signals Received Power (RSRP) at the base station 20 andthe RSRP at the user equipment 10. Thus, depending on the azimuthdirection, the RSRP at the base station 20 follows line 80, while theRSRP at the user equipment 10 follows line 78. This is because of theadditional power that has been added by the second power amplifier 16,which causes the angle dependent received power to differ by the amountillustrated in FIG. 3b . In other words, the user equipment measures aweaker signal coming from the base station than the base stationmeasures as coming from the user equipment. This discrepancy causessignificant problems to the link since the user equipment 10, as per the5G standard, reports the transmission loss (path loss), based on theRSRP at the user equipment 10, to the base station 20 which in turnallocates resource blocks to the wireless radio system. Specifically,the control circuitry 15 comprises calculation circuitry and/orreporting circuitry. The calculation circuitry performs a calculation ofa transmission loss based on a difference between the transmission powerand the reception power. The reporting circuitry reports an indicationof the transmission loss to the base station. Since the transmissionloss does not account for the additional power provided by the secondpower amplifier 16 this discrepancy can cause the base station toallocate an incorrect number of resource blocks.

FIG. 4a illustrates an example resource block allocation, where resourceblocks are allocated by the base station using frequency divisionmultiplexing and time division multiplexing. In particular, resourceblocks are allocated for the downlink 60 from the base station and theuplink 62 to the base station. In this example, 12 resource blocks areillustrated in for each of the downlink 60 and the uplink 62. Theresource blocks 60, 62 are used for transfer of information between thebase station 20 and the user equipment 10. The number of resource blocksallocated (M′) by the scheduler at the base station 20 is based on apreviously known number of resource blocks (M) and the change in pathloss (ΔPL) calculated at the user equipment 10 and measured in dB. Inthe illustrated embodiment, the number of resource blocks is given by

$M^{\prime} = {M \times {10^{- \frac{\Delta PL}{10}}.}}$

For example, assuming the additional power of the second power amplifier16 at a given beam steering angle ϕ is 3 dB corresponding to the signalbeing transmitted by the antenna array having twice the power of signaltransmitted by the base station, then the path loss reported by the userequipment 10 will have a 3 dB error (ΔPL=3). This under reporting by theuser equipment translates into halving the number of allocated resourceblocks (M′=M×10^(−0.3)=0.5M), which is a loss of 50% in throughput. Onthe other hand, over reporting by 1 dB will cause the base station 20 toinitially select the wrong level of the Modulation and Coding Scheme(MCS) resulting in higher than expected packet error rate and thus aloss of throughput. Hence, counterintuitively, by increasing thetransmitted power the overall throughput of the wireless system can bereduced. FIG. 4b illustrates a resource block allocation, in which thenumber of resource blocks are allocated to each of the uplink 64 and thedownlink 66 is halved, for example, due to the described path losscalculation. Hence, by increasing the power of the signal transmittedfrom the user equipment 10, the number of resource blocks available fortransmission is halved.

The inventors have realised that this problem can be overcome bymodifying the user equipment 10 to compensate for this discrepancy. Insome embodiments the user equipment 10 corrects measurements of the pathloss by applying updates at the software level to a number of reports.In other words, where the path loss is included in calculations relevantto reporting power transmission for the purpose of resource allocation,a correction is applied to the path loss that is equal to the additionalpower provided by the second power amplifier 16. In particular, thefollowing reports of the uplink physical channels are corrected:

-   -   PRACH (Physical Random Access Channel)    -   SRS (Sounding Reference Signal)    -   PUSCH (Physical Uplink Shared Channel)    -   PUCCH (Physical Uplink Control Channel)    -   PHR (Power Headroom Reporting)

In particular the calculated path loss measure at the user equipment 10is adjusted by subtracting, from the original path loss measure, aquantity equal to the scan loss, i.e., the additional (beam steeringangle ϕ dependent) power provided by the second power amplifier 16. Wedenote this correction factor ΔT(ϕ). The original path loss measure iscalculated at the user equipment 10 by subtracting the base station 20transmitted power from the received RSRP measurement where the basestation 20 transmitted power is advertised by (transmitted from) thebase station during the sign-on/registration process. In particular, thefollowing corrections are applied to the reports of the physicalchannels.

The uplink PUSCH (Physical Uplink Shared Channel) power control at theuser equipment 10 is calculated including the subtraction of thecorrection factor AT(ϕ) from the path loss PL. For example, the PUSCHpower can be calculated as the minimum of the configured uplink transmitpower P_(CMAX) and the sum of the nominal user equipment transmit powerP_(0_PUSCH), the modulation and coding scheme offset Δ_(TF), the closedloop power control f, a quantity ten times the logarithm of allocatedresource blocks for PUSCH M_(RB) ^(PUCSCH), and the correction factorAT(ϕ) subtracted from the path loss PL multiplied by the fractionalpower control multiplier α which is set to compensate. The uplink PUSCH(Physical Uplink Shared Channel) power control modified by thecorrection factor can also be expressed as follows:

$\begin{matrix}{{P_{PUSCH}(\phi)} = {\min\left\{ \begin{matrix}P_{CMAX} \\{P_{O\_{PUSCH}} + {10{\log_{10}\left( M_{RB}^{PUSCH} \right)}} + {\alpha{PL}} - {\alpha{{AT}(\phi)}} + \Delta_{TF} + f}\end{matrix} \right.}} & (1)\end{matrix}$

where

-   -   P_(CMAX): Configured uplink transmit power    -   P_(O_PUSCH): Nominal user equipment transmit power    -   M_(RB) ^(PUSCH): Allocated Resource Blocks    -   α: Fractional power control multiplier    -   PL: Path loss measurement (original)    -   Δ_(TF): Modulation and coding scheme offset    -   f: Closed loop power control

Equation (1) could further be modified to define the uplink PUSCH powerincluding any additional terms incorporated as part of the 5G standardwhere the path loss PL is modified to incorporate the correction factorAT(ϕ). The fractional power control multiplier α is a value between 0and 1 that determines the effect of path loss PL compensation in theuplink PUSCH power. In conventional power control scenarios, uplinkSignal to Interference Noise Ratio (SINR) is kept constant. As the userequipment increases its distance to the base station, the path lossincreases, and to maintain constant uplink SINR the power of the userequipment increases to cancel the path loss effect. This is achieved bysetting α=1. In fractional power control scenarios, the base stationallows for the uplink SINR to reduce as the distance of the userequipment increases. This is achieved by setting the control multiplierα to a value less than 1. The key benefit of fractional power control isto reduce inter-cell interference and hence boost the average cellthroughput.

The corresponding uplink PUCCH (Physical Uplink Control Channel) powercontrol at the user equipment 10 is calculated including the subtractionof the correction factor AT(ϕ) from the path loss PL. For example, thePUCCH power can be calculated as the minimum of the configured uplinktransmit power (P_(CMAX)) and the sum of the nominal user equipmenttransmitted power for the PUCCH (P_(O_PUCCH)), the PUCCH format offset(Δ_(F_PUCCH)), the closed loop power control explicit for the PUCCH (g),the modulation and coding scheme offset (Δ_(TF)), a quantity ten timesthe logarithm of allocated resource blocks for PUCCH (M_(RB) ^(PUCCH)),and the correction factor (AT(ϕ)) subtracted from the path loss (PL).The uplink PUCCH (Physical Uplink Control Channel) power controlmodified by the correction factor can also be expressed as follows:

$\begin{matrix}{{P_{PUSCH}(\phi)} = {\min\left\{ \begin{matrix}P_{CMAX} \\{P_{O\_{PUSCH}} + {10{\log_{10}\left( M_{RB}^{PUSCH} \right)}} + {PL} - {{AT}(\phi)} + \Delta_{F\_{PUCCH}} + \Delta_{TF} + {fg}}\end{matrix} \right.}} & (2)\end{matrix}$

where

-   -   P_(O_PUCCH): Nominal user equipment transmit power for the PUCCH    -   M_(RB) ^(PUCCH): Allocated Resource Blocks for the PUCCH    -   Δ_(F_PUCCH): PUCCH Format offset    -   g: Closed loop power control explicit for the PUCCH

Equation (2) could further be modified to define the uplink PUCCH powerincluding any additional terms incorporated as part of the 5G standardwhere the path loss PL is modified to incorporate the correction factorAT(ϕ).

The corresponding SRS (Sounding Reference Signal) power control at theuser equipment 10 is calculated including the subtraction of thecorrection factor AT(ϕ) from the path loss PL. For example, the SRSpower can be calculated as the minimum of the configured uplink transmitpower (P_(CMAX)) and the sum of the nominal user equipment transmittedpower for the SRS (P_(O_SRS)), the closed loop power control explicitfor the SRS (h), a quantity ten times the logarithm of allocatedresource blocks for SRS (M_(SRS)), and the correction factor (AT (ϕ))subtracted from the path loss (PL) multiplied by the fractional powercontrol multiplier for SRS (α_(SRS)). The uplink SRS (Sounding ReferenceSignal) power control modified by the correction factor can also beexpressed as follows:

$\begin{matrix}{{P_{SRS}(\phi)} = {\min\left\{ \begin{matrix}P_{CMAX} \\{P_{O\_{SRS}} + {10{\log_{10}\left( M_{SRS} \right)}} + {\alpha_{SRS}{PL}} - {\alpha_{SRS}\ {{AT}\ (\phi)}} + h}\end{matrix} \right.}} & (3)\end{matrix}$

where

-   -   P_(O_SRS): Nominal UE transmit power for the SRS    -   M_(SRS): Allocated Resource Blocks for the SRS    -   α_(SRS): Fractional power control multiplier for SRS    -   h: Closed loop power control explicit for the SRS

Equation (3) could further be modified to define the uplink SRS powerincluding any additional terms incorporated as part of the 5G standardwhere the path loss PL is modified to incorporate the correction factorAT(ϕ). The fractional power control multiplier α_(SRS) is a valuebetween 0 and 1 that determines the effect of path loss compensation inthe uplink SRS power. As discussed above in relation to α, when the userequipment increases its distance to the base station, the path lossincreases, and to maintain constant uplink SINR the power of the userequipment increases to cancel the path loss effect. This is achieved bysetting α_(SRS)=1. In fractional power control scenarios, the basestation allows for the uplink SINR to reduce as the distance of the userequipment increases. This is achieved by setting the control multiplierα_(SRS) to a value less than 1. The key benefit of fractional powercontrol is to reduce inter-cell interference and hence boost the averagecell throughput.

The corresponding PRACH (Physical Random Access Channel) power controlat the user equipment 10 is calculated including the subtraction of thecorrection factor AT(ϕ) from the path loss PL. For example, the PRACHpower control can be calculated as the minimum of the configured uplinktransmit power (P_(CMAX)) and the sum of the configured uplink transmitpower (P_(CMAX)) and the path loss (PL) modified to incorporate thecorrection factor (AT(ϕ)). The PRACH (Physical Random Access Channel)power control can also be expressed as follows:

$\begin{matrix}{{P_{PRACH}(\phi)} = {\min\left\{ \begin{matrix}P_{CMAX} \\{P_{CMAX} + {PL} - {{AT}(\phi)}}\end{matrix} \right.}} & (4)\end{matrix}$

Equation (4) could further be modified to define the uplink PRACH powerincluding any additional terms incorporated as part of the 5G standardwhere the path loss PL is modified to incorporate the correction factorAT(ϕ).

The PHR (Power Headroom Reporting) calculations at the user equipment 10also includes the correction factor calculated, including thesubtraction of the correction factor AT(ϕ) from the path loss PL. Theuser equipment 10 sends the power headroom to the base station 20 wherethe scheduler uses the power headroom to compute the path loss and toderive the number of resource blocks. There are two types of powerheadroom: PH_(type 1)(ϕ) and PH_(type 3)(ϕ) which correspond to thepower headroom report based on an actual PUSCH transmission and a powerheadroom report based on an actual SRS transmission respectively. Ratherthan computing the minimum of two quantities as defined in equations (1)and (3) for PUSCH and SRS respectively, the power headroom calculatesthe difference between these quantities. A positive PHR indicatedavailability of power, a negative value indicates the UE has reached itsmaximum transmit power. Specifically, PH_(type 1)(ϕ) and PH_(type 3)(ϕ)are defined as:

PH_(type1)(ϕ)=P _(CMAX) −{P _(O_PUSCH)+10 log₁₀(M _(RB)^(PUSCH))+αPL−αAT(ϕ)+Δ_(TF) +f}  (5)

PH_(type3)(ϕ)=P _(CMAX) −{P _(O-SRS)+10 log₁₀(M_(SRS))+α_(SRS)PL−α_(SRS)AT(ϕ)+h}  (6)

Equations (5) and (6) could further be modified to define the uplinkpower head room including any additional terms incorporated as part ofthe 5G standard where the path loss PL is modified to incorporate thecorrection factor AT(ϕ).

By correcting the uplink reports at the user equipment 10, thediscrepancy introduced by the correction factor AT(ϕ) at the secondpower amplifier 16 for a beam steering angle ϕ is corrected at the userequipment 10 and, as a result, an increased throughput can be achievedcorresponding to the increased signal power achieved by the second poweramplifier 16.

FIG. 5 schematically illustrates an alternative embodiment in which thisdiscrepancy is corrected by including the correction factor AT(ϕ) at thehardware level. In the illustrated embodiment user equipment 50communicates with base station 20. User equipment 50 comprises a numberof components that are already described with reference to FIG. 1.Hence, only the additional components will be described in detail here.The user equipment 50 comprises an antenna system 54 which furthercomprises second power amplifier 16 and beam steering circuitry 18. Inaddition, antenna system 54 comprises low noise amplifier 52 to amplifythe signal received from the base station without significantlydegrading its signal-to-noise ratio. Signals received from the basestation 20 by the antenna array 22 are passed by antenna system 54through the low noise amplifier 52 before being passed to the basebandand RF unit 14. The low noise amplifier 54 amplifies the received signalby a gain that is dependent on the correction factor AT(ϕ) which isdependent on the beam steering angle ϕ, and is chosen to be equal to thegain of the second power amplifier 16 for all beam steering angles ϕ. Inthis way the discrepancy introduced by the second power amplifier 16 iseliminated prior to the calculation of the transmission loss by thecalculation circuitry of the control circuitry 15 and prior to thereception of the signal at the baseband and RF unit, resulting in anincreased transmission efficiency as a result of the increased signalpower. Thus, the inclusion of the low noise amplifier 54 eliminates theneed for including the correction factor AT(ϕ) at the software level.

FIG. 6a schematically illustrates a sequence of steps carried out by thebase station 20 according to some examples of the present technology. Atstep S60 the base station transmits and receives resource blocks withuser equipment 10 based on a current resource block allocation, forexample, as illustrated in FIG. 4a . At step S62 the base station 20receives an indication of a path loss from the user equipment 10. Atstep S64 the base station calculates a new resource block allocation andindicates the new resource block allocation to the user equipment 20(UE). Flow then returns to step S60.

FIG. 6b schematically illustrates a sequence of steps carried out by theuser equipment 10 communicating with the base station 20 according tosome examples of the invention. The base station 20 is assumed toundertake the sequence of steps set out in FIG. 6a . At step S70 theuser equipment 20 (as illustrated in FIG. 1) uses antenna control 26 andbeam steering circuitry 18 to set the beam steering angle ϕ based on arelative direction of the base station. At step S72 the user equipmentamplifies the signal to be output by the correction factor AT(ϕ). Thecorrection factor AT(ϕ) is set equal to the power added or subtracted in16 PA2. At step S74 the user equipment 10 transmits the amplified signalat angle ϕ to the base station 20 based on a resource block allocationthat has been received from the base station 20 in accordance with thesteps set out in FIG. 6a . At step S76 the user equipment 10 receives asignal at the angle ϕ from the base station 20. At step S78 the userequipment calculates the path loss based on a difference between thepower of the transmitted signal from the base station and the receivedsignal at the user equipment. As the transmitted signal has beenamplified by the correction factor AT(ϕ), there will be a discrepancybetween the transmitted and received power based on the correctionfactor AT(ϕ) and based on the transmission losses. At step S80 the pathloss is corrected in software at the user equipment 10 by subtractingthe correction factor AT(ϕ) from the path loss during calculation of thePRACH (Physical Random Access Channel) power, the SRS (SoundingReference Signal) power, the PUSCH (Physical Uplink Shared Channel)power, the PUCCH (Physical Uplink Control Channel) power, and the PHR(Power Headroom Reporting). At step S82 the user equipment transmitssignals containing an indication of the corrected path loss to the userequipment, for example, through transmission of the PHR corrected by thecorrection factor set out in equations (5) and (6). At step S84, theuser equipment receives a resource block allocation from the basestation 20 based on the path loss. Flow then returns to step S70.

FIG. 6c schematically illustrates a set of steps carried out in thealternative embodiment illustrated in FIG. 5. The base station 50 isassumed to undertake the sequence of steps set out in FIG. 6a . StepsS70-S76 are identical to those described in FIG. 6b . At step S86 thesignal that has been received at an angle ϕ is amplified by low noiseamplifier 52 by the correction factor AT(ϕ). At step S88 the userequipment 50 calculates the path loss based on a difference between thepower of the transmitted signal at the base station and the power of theamplified received signal (i.e., the signal that was received in stepS76 and then subsequently amplified in step S86). As both thetransmitted signal and the received signal have each been amplified bythe correction factor AT(ϕ), the discrepancy between the transmitted andreceived power based on the correction factor AT(ϕ) (as described withreference to FIG. 6b , step S78) is already accounted for and there isno need to apply the software based correction factors as described inFIG. 6b , step S80. At step S90 the user equipment 50 transmits a signalincluding an indication of the path loss to the base station 20. Flowthen returns to step S84 which is identical to that described inreference to FIG. 6 b.

Of course, it will be appreciated that in some embodiments, the pathloss that is transmitted to the base station in FIG. 6b could be basedon the correction factor (e.g. by adding, subtracting, multiplying ordividing by a constant that can be determined at the base station side).Similarly, the correction factor that is used in FIG. 6c for performinggain adjustment of the incoming signal could be adjusted in other waysfor other purposes not directly relevant to the present disclosure.

FIG. 7 schematically illustrates a sequence of steps according to someembodiments of the invention. At step S91 the wireless radio systemadjusts, based on a scan loss of an outgoing signal due to beamforming,a transmission power of the outgoing signal by a scan loss adjustmentamount to produce an adjusted signal. At step S92 the wireless radiosystem transmits the adjusted signal. At step S94 the wireless radiosystem receives an incoming signal at a reception power. Finally, atstep S96 the wireless radio system adjusts the reception power of theincoming signal based on the scan loss adjustment amount to produce anadjusted input signal.

FIG. 8 schematically illustrates a sequence of steps according to someembodiments of the invention. In particular, FIG. 8 relates toembodiments in which the path loss calculation is corrected by the useof software. In these embodiments, at step S100, a scan loss of anoutgoing signal due to beamforming is determined. At step S102, atransmission power of the outgoing signal is adjusted by a scan lossadjustment amount. At a step S104, the adjusted signal is transmitted.At a step S106, an incoming signal is received at a reception power. Atstep S108, the path loss is calculated (e.g. by control circuitry 15)and is adjusted (e.g. by the control circuitry 15) as previouslydescribed. For example, the previously described correction factor AT(ϕ)could be added to the path loss calculation. Then, the corrected pathloss is reported (e.g. to a base station) in step S110.

In brief overall summary at least some embodiments provide a wirelessradio system comprising: compensation circuitry to adjust, based on ascan loss of an outgoing signal due to beamforming, a transmission powerof the outgoing signal by a scan loss adjustment amount to produce anadjusted signal; transmission circuitry to transmit the adjusted signal;reception circuitry to receive an incoming signal at a reception power;input adjustment circuitry configured to adjust the reception power ofthe incoming signal based on the scan loss adjustment amount to producean adjusted input signal.

In the present application, the words “configured to . . . ” are used tomean that an element of an apparatus has a configuration able to carryout the defined operation. In this context, a “configuration” means anarrangement or manner of interconnection of hardware or software. Forexample, the apparatus may have dedicated hardware which provides thedefined operation, or a processor or other processing device may beprogrammed to perform the function. “Configured to” does not imply thatthe apparatus element needs to be changed in any way in order to providethe defined operation.

Although illustrative embodiments have been described in detail hereinwith reference to the accompanying drawings, it is to be understood thatthe invention is not limited to those precise embodiments, and thatvarious changes, additions and modifications can be effected therein byone skilled in the art without departing from the scope and spirit ofthe invention as defined by the appended claims. For example, variouscombinations of the features of the dependent claims could be made withthe features of the independent claims without departing from the scopeof the present invention.

1. A wireless radio system comprising: compensation circuitry to adjust,based on a scan loss of an outgoing signal due to beamforming, atransmission power of the outgoing signal by a scan loss adjustmentamount to produce an adjusted signal; transmission circuitry to transmitthe adjusted signal; reception circuitry to receive an incoming signalat a reception power; calculation circuitry to perform a calculation ofa path loss based on a difference between the transmission power and thereception power, and to adjust the path loss; and reporting circuitry toreport an indication of the path loss adjusted by the calculationcircuitry to the base station, wherein the calculation circuitry adjuststhe path loss based on the scan loss adjustment amount.
 2. The wirelessradio system according to claim 1, wherein the scan loss adjustmentamount is limited to a maximum value so that the adjusted signal'stransmission power is below a regulatory limit.
 3. The wireless radiosystem according to claim 1, wherein the transmission circuitrycomprises an antenna array to steer a transmission beam corresponding tothe outgoing signal at a plurality of angles, wherein the scan loss isdependent on a steered direction, which is one of the plurality ofangles at which the transmission beam is steered.
 4. The wireless radiosystem according to claim 3, wherein a gain at the steered angle of thetransmission beam transmitted at the steered angle is below a gain at apeak transmission angle of the transmission beam transmitted at thesteered angle
 5. The wireless radio system according to claim 3, whereinthe scan loss is a difference between a maximum gain of the antennaarray across all of the plurality of angles and a maximum gain of thetransmission beam transmitted at the steered angle.
 6. The wirelessradio system according to claim 1, wherein the transmission circuitry isadapted to transmit the adjusted signal to a wireless node during asubset of a plurality of resource blocks; and the reception circuitry isadapted to receive the incoming signal from the wireless node.
 7. Thewireless radio system according to claim 6, wherein the wireless node isconfigured to allocate the subset of the plurality of resource blocks tothe wireless radio system.
 8. The wireless radio system according toclaim 6, wherein the wireless node is configured to allocate the subsetof the plurality of resource blocks to the wireless radio system basedon the path loss reported by the reporting circuitry of the wirelessradio system.
 9. The wireless radio system according to claim 1, whereinthe path loss is adjusted by compensating for the scan loss adjustmentamount.
 10. The wireless radio system according to claim 1, wherein thepath loss is adjusted by discounting the scan loss adjustment amount.11. The wireless radio system according to claim 1, wherein thecompensation circuitry is an amplifier.
 12. The wireless radio systemaccording to claim 1, wherein the outgoing signal and the adjustedsignal are RF signals.
 13. The wireless radio system according to claim1, comprising: further compensation circuitry to adjust a power of abaseband signal to produce the outgoing signal at the transmissionpower.
 14. A method comprising: adjusting, based on a scan loss of anoutgoing signal due to beamforming, a transmission power of the outgoingsignal by a scan loss adjustment amount to produce an adjusted signal;transmitting the adjusted signal; receiving an incoming signal at areception power; performing a calculation of a path loss based on adifference between the transmission power and the reception power, andto adjust the path loss; and reporting an indication of the path lossadjusted by the calculation circuitry to the base station, wherein thepath loss is adjusted based on the scan loss adjustment amount.
 15. Awireless radio system comprising: means for adjusting, based on a scanloss of an outgoing signal due to beamforming, a transmission power ofthe outgoing signal by a scan loss adjustment amount to produce anadjusted signal; means for transmitting the adjusted signal; means forreceiving an incoming signal at a reception power; means for performinga calculation of a path loss based on a difference between thetransmission power and the reception power, and to adjust the path loss;and means for reporting an indication of the path loss adjusted by thecalculation circuitry to the base station, wherein the path loss isadjusted based on the scan loss adjustment amount.